Incinerator



E. F. BOLDA Sept. 25, 1962 INCINERATOR 7 Sheets-Sheet 1 Filed July 3.6, 1958 R M T L 0 B m... D R A W D E ATTORNEYS Sept. 25, 1962 E. F. BOLDA 3,055,320

INCINERATOR Filed July 16, 1958 7 Sheets-Sheet 3 INVENTOR EDWARD F. BOLDA BY WM4.M

AT TORN EY5 Sept. 25, 1962 E. F. BOLDA 3,055,320

INCINERATOR Filed July 16, 1958 '7 Sheets-Sheet 4 ATTORNEYS Sept. 25, 1962 E. F. BOLDA INCINERATOR 7 Sheets-Sheet 6 I Filed July 16, 1958 FIG.6

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EDWARD BY MWW/ ATTORNEYS E. F. BOLDA Sept. 25, 1962 INCINERATOR 7 Sheets-Sheet '7 Filed July 16, 1958 FIG. 8

1 mHHHH W4 @Wu ATTORNEYS United States Patent 3,055,320 INCIINERATOR Edward F. Bolda, 6103 N. River Road, Des Plaines, Ill. Filed July 16, 15 58, Ser. No. 748,935 (Ilaims. (Cl. 110-15) This invention relates to an incinerator and in particular to the handling of air flow within the incinerator.

Incinerators built on the scale of a municipal installation have been constructed to include a hopper into which the refuse is to be charged for flow onto grates and from the grates into a rotary kiln. The present invention is concerned with this known generalized structure, and the primary object of the present invention is to account for an advantageous flow of air through the incinerator in respect of the flow of refuse material. Other objects of the present invention are to produce more effective drying of the refuse material prior to passage thereof into the burning areas of the incinerator; to account for more complete removal of incinerator odors; to embody many desirable features in -a more simplified incinerator construction; and to produce effective settling out of what would normally be entrained particles in the combustion gases emitted from the stack of the incinerator.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principle thereof and what is now considered to be the best mode contemplated for applying this principle. Other embodiments of the invention embodying the same or equivalent principle may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a side elevation of an incinerator construction embodying the features of the present invention;

FIG. 2 is a sectional view on an enlarged scale of the grate section and the kiln of the incinerator shown in FIG. 1, with the grates thereof shown in elevation in somewhat diagrammatic form;

FIG. 3 is an elevational view substantially on the scale of FIG. 2. showing the plan of the forced air means;

FIG. 4 is a horizontal sectional view of the grate section, subsidence chamber, the stack and the pipe connecting the stack and subsidence chamber;

FIG. 5 is a vertical sectional view on an enlarged scale of the subsidence chamber;

FIG. 6 is a sectional view of the burning area of the grate section;

FIG. 7 is an elevation of a grate unit;

FIG. 8 is a fragmentary detailed view, partly in section and partly in elevation, illustrating the path of air flow from one of the air ducts embodied in the invention into the rotary kiln; and

FIG. 9 is a fragmentary elevational view on line 99 in FIG. 8 showing the opening between the duct and rotary kiln as shown in FIG. 8.

The incinerator of the present invention includes a hopper at an elevated position and into which the refuse to be burned is charged by means of an overhead crane or the like. The discharge end of this hopper opens into the grate section of the incinerator, and the grate section in turn terminates at the input end of a rotary kiln. The kiln as well as the pusher grates in the grate section are arranged on an incline so that the refuse normally tends somewhat to flow by gravity therein, and the lower or output end of the kiln is disposed above a water quench pit into which the non-cornbustibles are discharged for eventual removal to a separation area.

The present invention is concerned primarily with the flow of air used for combustion and the manner in which the dust-laden combustion gases are handled to cause the particles entrained therein to be consumed or settled out to reduce emission thereof from the stack of the incinerator.

Referring to FIG. 1 of the drawings, the refuse to be handled is fed into the open upper end of a hopper 26, and as shown in FIG. 2 this hopper has a lower discharge end leading to a main grate section wherein pusher grates, FIG. 7, are mounted for reciprocation as will be explained. The grate section of the incinerator is divided into a drying grate area 25, FIG. 2, and a burning grate area 26, and as shown by legend in FIG. 2 the grates are arranged within these two areas so that the grate line extends downwardly along an incline proceeding from the charging hopper 20 in the direction of a rotary kiln 30 The grates which operate within the grate section are of a known construction illustrated in FIG. 7, and each operative grate assembly includes fixed grate bars 31 and movable grate bar pairs 32 on opposite sides fore and aft of the fixed grate bars. The movable grate bars are mounted on heads 33, and these in turn are fixed to a reciprocating bar 34 adapted to be moved by a piston and cylinder arrangement or any other suitable means. The grate bars are so spaced as to allow the fines to drop therethrough into a primary collecting bin 36, FIG. 1, associated with the drying grate area and another bin 37, having a plurality of access doors 37a disposed at ground level beneath the burning grate area. Hence, refuse small enough to pass through the grates is collected in receiving bins beneath the grates while the material remaining on the grates is advanced gradually through the incinerator for further drying and burning.

It should be pointed out that the major amount of combustion occurs in the burning area 26 and within the kiln 30 and the refuse is prepared for effective combustion during the course of its movement through the initial drying area 25. It should be pointed out that at this stage, drying is materially facilitated by a radiation effect encouraged by a slope-d refractory lining 40 on the wall of the grate section above the two grate areas 25 and 26. This lining or roof is sloped downwardly proceeding toward the kiln 30, and the lining is rounded at 40R to account for more effective radiation of heat inwardly toward the central portion of the drying area 25. It should moreover be pointed out that the source of radiation heat in this instance is hot gases which are travelling in a counter flow path upwardly through the grate areas 25 and 26 just prior to moving over the top of bridge wall 45, FIG. 2, which leads to the subsidence chamber to be described hereinafter.

The rotary kiln 30 is mounted for rotation on an axis which is inclined. Stated in other Words, the end of the kiln 30 which communicates with the grate bars at the lower discharge end of the burning area 26 is in an elevated position with the opposite or discharge end of the kiln 31) at a lower position. It will be realized that the structure so far described, and that to be described hereinafter, is erected from structural steel, common brick and refractory brick in accordance with the established architectural principles, and hence the superstructure, Wall construction and linings are not described in detail.

Thus, it will be seen that the flow of refuse in the present instance is downward from the hopper 20, onto the grates in the drying area 25. The grates in the burning area are dropped below the grates in the drying area, so that the refuse emitting from the drying area of the grate section tumbles or cascades onto the burning grates 26 resulting in mixing. From the grate section, the refuse is discharged into the input end of the rotary kiln 30 and from the discharge or output end of the rotary kiln 30 into the quench pit QP, FIG. 1.

One of the primary features of the present invention is the way in which air is furnished to the grate section and the kiln of the incinerator, and it should be explained at this point that the incinerator includes the usual stack 50 which cooperates to establish the essential and necessary draft. The stack 50 is located at one side of the kiln 30 and is connected by a large pipe 51 to the output end of a subsidence chamber generally indicated at 55 in FIG. 1. This subsidence chamber at the opposite end in turn is connected to the upper end of the drying area of the grate section so as to communicate therewith, and this connection is at the bridge wall 45 so that the heavy draft air, as will be explained, flows upwardly over the bridge wall 45 with advantageous results.

In establishing the essential and necessary draft, a draft door is arranged to admit a draft of air into the lower end of the rotary kiln 30 so that there will be a heavy draft upward through the kiln and grate section of the incinerator in a flow that is counter to the downward how of refuse material. Thus, in the present instance, a draft door 56, FIG. 1, is located at the forward side of a shack 57 which is conveniently afforded at the discharge end of the kiln 3t} and above the quench pit QP. This shack 57 is nothing more than a convenient hood-type enclosure for the discharge end of the kiln 30 and some of the equipment associated with conveyor mechanism submerged in the quench pit to move the unconsumed materials such as slag, ash, iron and the like from the quench pit to a receiving area.

In addition to the natural draft thus created between the stack 50 and the draft door 56, means are afforded in the present instance to establish a forced draft of air upward between the grates in the burning area 26, inward from the side walls of the burning area of the grate section, downward through the burning area of the grate section in a flow parallel to the flow of refuse, to the kiln at the upper end thereof also in a flow parallel to the flow of refuse material, and a further forced draft at the bridge wall joining the grate section and the subsidence chamber. In this way, a heavy degree of turbulence is created within the kiln and within the burning area of the grate section above the refuse level due to the counter movements of air therein. The net result of this is a high degree of combustion of the dust or refuseparticle laden atmosphere within the kiln and within the burning area of the grate section assuring, in the first instance, the least amount of entrained particles in the stack gases emitted by the stack. Additionally, this turbulent combustion above the refuse level in the incinerator accounts for a great deal of elimination of undesired, unpleasant odorous gases containing the smallest entrained particles. Additionally, this heavy burning of the gases above the solid refuse contributes to effective drying in the drying area of the grate section and hence much more effective combustion of the solids in the burning areas.

The source of forced air is a large rotary fan 60, FIGS. 1 and 3 which has the main output duct 61 thereof connected by an air duct 66 to an air chamber 65, which constitutes the interior of the bin 37. The air chamber 65 is in communication with a passage 63, FIG. 2, which opens into the rotary kiln. As shown in FIG. 3, the air chamber 65 is located beneath the grates in the burning area, so that under-fired forced air will be directed up wardly through the grates in the burning area. Additionally, a pair of ducts 67 and 68, FIG. 3, are in communication with the main duct 61 of the fan 60. These ducts 67 and 68 are connected to conduits 70 and 71. The conduit 70 supplies forced air to a relatively large jet nozzle 74 located between the burning area and the drying area and which is arranged to direct forced air into the burning area at a point above the normal refuse level.

As shown in FIG. 2, the forced fan air and natural draft air flow in opposite directions within the kiln 30 as well as within the burning area of the grate section creating the desired turbulence referred to above.

Conduit 71 which is connected to duct 68 is directed upwardly and away from the conduit 70 and leads to a manifold (not shown) which furnishes forced air to a plurality of jet nozzles 75, FIG. 2, which are located on the bridge wall 45 to cooperate with the draft air flowing over the bridge wall in creating turbulence and effective combustion of refuse gases at the bridge wall.

Referring to FIG. 6, the side walls 77 and 78 of the grate section at the burning area thereof are equipped with air jets for directing forced air from the fan into the burning area above the grate line in a direction normal to the flow of the natural draft. In accomplishing this, a pair of side ducts 79 and 80 are arranged to receive forced air from the fan, and these ducts are mounted in the side walls 77 and '78 to direct air into headers or manifolds 81 which in turn furnish air to outlet openings 82 of restricted diameter. Excess air furnished to the jets 82 is drained off by a pair of conduits 84 and 85, and these open into the chamber 65.

Reference was made above to the rounded wall 40R in FIG. 2. which is located on the grate section side of the bridge wall 45. It will be observed that this wall is so located and is configured in a convex fashion to radiate heat from the burning grates and over-fired air onto the refuse moving through the drying area 25 thereby further enhancing drying of the refuse being charged into the burning area. Considerable steaming and generation of undesired odors occurs within the drying area particularly insofar as intense drying is encouraged together with some light burning. Moreover, a great deal of combustion of the gases above the refuse level occurs at the grate section side of the bridge wall.

As a result of the rise of the draft air over the bridge wall into the subsidence chamber, large quantities of flyash will tend to settle on the subsidence chamber side of the bridge wall, and further settling of solids carried by the stream of draft air is encouraged within the subsidence chamber as will now be explained.

The general arrangement of the subsidence chamber is illustrated with particularity in FIGS. 4 and 5 as embodied in an elongated housing 86 including closed side walls 86m and 8615, a closed end wall 86c adjacent the hopper 20 and a closed top wall 87. The opposite end wall 86d of the subsidence chamber is open at 88, and this opening communicates with the pipe 51 referred to above. It Will be noted that dampers 90 and 91 are located in the pipe 51.

The subsidence chamber 55 is sub-divided into a plurality of settling areas by bridge walls 92 which are disposed in vertical planes, and each settling area includes a fiy-ash hopper 93 for the entrained particles which settle out of the incinerator gases moving toward the stack. These bridge walls are so arranged as to define a tortuous path for the dust-laden air traveling through the subsidence chamber. Thus, as will be observed in FIGS. 4 and 5, each bridge wall is shortened laterally between the side walls 86a and 86b as well as vertically between the top wall and collecting hoppers in an alternating fashion. Hence, there is a side-winder effect in a horizontal direction as well as a vertical direction on the air travelling through the subsidence chamber, and considerable settling out occurs in progressively lessening quantities from one settling area to the next in the subsidence chamber. Resultantly, the gases out of the stack are relatively clean and odor free.

It will be seen from the foregoing that the refuse material under the present invention moves down through the grate secion and the rotary kiln in a direction counter to the path of the natural draft. The drying grate area has a length of between ten and eighteen feet as an optimum range, and the grates therein can be inclined at an angle of 15 to 45. The second set of grates in the burning area is disposed two to five feet below the drying area grates and at an incline of to 30. The fire grate carries the fire forward a distance of fifteen to twenty-five feet into the refractory lined kiln set at an angle of 5 to 20".

In addition to the counter-flow natural draft, there is a forced draft of air into the burning area and into the rotary kiln counter to the natural draft, creating heavy turbulence in the rotary kiln and above the burning grates. This turbulence is further encouraged by forced air over the burning grate normal to the aforementioned flow of air. About fifty percent of the refuse has been consumed by the time is reaches the rotary kiln 30, and the final act of solids combusion occurs within the rotary kiln.

As the overfired air and hot gases move upward over the burning grates, the forced air discharged from the nozzle 82 contributes to efiicient burning of the contaminated atmosphere over the burning grates, and a large percentage of the odorous gases are consumed at this time. The heat developed in the drying area 25 is eifectively radiated into the drying area as has been explained, causing quick drying and evaporation. The steam and orors given off at this point are swept over the bridge wall 45, and the jets 75 furnish air for combustion of what is moving into the subsidence chamber. There will be a heavy deposit of fly-ash in the first settling area subchamber on the far side of the bridge wall, and next movement of the gases through the subsidence chamber is under the clockwise around the left-most bridge wall 92 as viewed in FIGS. 4 and 5. The next movement is over the top and counterclockwise around the second bridge wall 92, and so on until finally the relatively clean and odor free gases reach the pipe 51 and from thence to and up the stack 50.

Hence, while I have illustrated and described a preferred embodiment of my invention, it is to be understood that this is capable of variation and modification, and I therefore do not Wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In an incinerator having a stack, a hopper at an elevated position into which refuse is to be charged for eventual incineration, said hopper having a lower discharge end, a grate section including a first set of grates on which drying refuse is to occur and having a terminal upper end positioned adjacent the discharge end of the hopper to receive refuse therefrom, said grate section including a second set of grates on which burning of the refuse is to occur, said sets of grates being arranged in downwardly inclined cascaded relation to enable the refuse to move through the grate section along a downward incline, means affording a subsidence chamber adjacent the grate section, said subsidence chamber extending generally parallel to the grate section at one side thereof and being in communication with the grate section at one end and with the stack of the incinerator at the other end and including a plurality of vertically disposed bridge walls therein defining a tortuous path for gases moving therethrough toward the stack, a rotary kiln arranged on an inclined axis and having an upper end to receive refuse from the second set of grates, said kiln having a lower discharge end from which refuse is to be discharged, means for admitting forced air into the burning area of the grate section and into the kiln in the direction of refuse flow, means for admitting a draft into the discharge end of the kiln and into the grate section to move longitudinally therethrough in a path counter to the path of forced air and refuse movement through the kiln and counter to the flow of refuse movement through the grate sections; and a vertically disposed bridge wall adjacent the upper end of the grate section where the grate section and subsidence chamber are in communication and over which the counter flow draft flows from the grate section directly into the subsidence chamber.

2. An incinerator according to claim 1 wherein means are afforded to admit forced air into the burning area above the grates along a lateral path generally normal to the flow of draft air and to furnish forced air to outlets located adjacent the bridge wall connecting the grate section and the subsidence chamber.

3. An incinerator according to claim 1 wherein the grate section has a roof portion thereover which is rounded in a convex fashion at a point adjacent the last-named bridge wall to radiate heat into the firstnamed grate section.

4. In an incinerator, a hopper at an elevated position into which refuse is to be charged for eventual incineration, said hopper having a lower discharge end, a grate section wherein burning of the refuse is to occur and having a terminal upper end positioned adjacent the discharge end of the hopper to receive refuse therefrom, said grate section having a terminal lower discharge end and including movable grates arranged in a downward incline proceeding in a direction from the terminal upper end toward the terminal lower end of the grate section to move the refuse through the grate section along a downward incline, a rotary kiln arranged on an inclined axis and having an upper end to receive refuse from the grate section, said kiln having a lower discharge end from which refuse is to be discharged, means for admitting forced air into the grate section and into the kiln in the direction of refuse flow, means for admitting a draft into the discharge end of the kiln and the discharge end of the grate section to flow longitudinally therethrough in a path counter to the path of forced air and refuse movement, and a stack for discharging waste combustion gases, said grate section being in communication at the upper end thereof with the inlet end of a subsidence chamber and separated therefrom by a vertical bridge wall immediately adjacent the grate section and said subsidence chamber, said subsidence chamber leading to the stack.

5. An incinerator according to claim 4 wherein the subsidence chamber extends generally parallel to and along one side of the grate section and which is defined by a plurality of bridge walls defining a torsion path for the gases to the stack.

References Cited in the file of this patent UNITED STATES PATENTS 1,408,972 Bell Mar. 7, 1922 1,627,349 Snow May 3, 1927 1,642,586 Lewis Sept. 13, 1927 1,714,005 Dru May 21, 1929 1,859,300 Krenz May 24, 1932 2,015,842 Christensen Oct. 1, 1935 2,238,161 Drew et al. Apr. 15, 1941 2,269,273 Krogh et al. Jan. 6, 19'42 FOREIGN PATENTS 29,483 Great Britain Dec. 16, 1909 463,477 France Feb. 24, 1914 802,952 France June 22, 1936 

